In the field of marine engines, it is known to monitor the performance of such engines by using a temperature sensor and a pressure transducer. However, pressure transducers are subject to experiencing dynamic loads which limit their working lives. Moreover, a pressure transducer and a temperature sensor need to be provided for each cylinder of the engine, and so for a twelve cylinder engine, twelve channels of instrumentation need to be provided (with two or more sensors to each). Such known methods use analysis of the Otto engine cycle.
We have devised an improved way of monitoring engine performance, and in particular, although not exclusively, marine engine performance.